1. Field of the Invention
The present invention is related to a photodetector and a fabricating method thereof, and particularly to an organic photodetector and a fabricating method of an organic photodetector and an organic thin film transistor (OTFT).
2. Description of Related Art
Photodetectors can be divided into inorganic photodetectors and organic photodetectors according to their different materials. Inorganic photodetectors have been extensively applied in many things, such as the charge-coupled device (CCD), the complementary metal-oxide semiconductor (CMOS) and the sensing component. In contrast to the inorganic photodetector, the organic photodetector has better characteristics than those of the inorganic photodetector, such as flexibility, low fabricating temperature and so forth.
FIG. 1 illustrates a schematic cross-sectional view of a conventional organic photodetector. Referring to FIG. 1, an organic photodetector 100 includes a transparent substrate 110, an anode 120, an organic layer 130, a stop layer 140 and a cathode 150. When photons carrying enough energy enter the organic layer 130 from the substrate 110, the organic layer 130 would absorb the photons to form electron-hole pairs. Holes in the electron-hole pairs move towards the cathode 150 and the electrons move towards the anode 120 so that opto-electric currents are generated. Detection of the opto-electric currents can determine if there is any light entering the organic layer 130.
If the organic photodetector detects any light, an incident light needs to enter the organic layer so as to generate the opto-electric currents. The larger an irradiated area in the organic layer is, the higher the sensibility of the organic photodetector gets. Therefore, how to increase the irradiated area to improve the efficiency of the organic photodetector has become an important issue.